EM wave propagation and scattering in polarimetric SAR interferometry

In this paper we develop a multi-layer coherent polarimetric vegetation scattering model to investigate physical parameter estimation using fully polarimetric multi-baseline multi-frequency radar interferometry. It is shown that 2-layer model inversion for single baseline/single frequency sensors requires regularisation to remove multiple solutions. Traditionally this is achieved by using assumptions about polarimetric ground scattering ratios. By employing dual frequency or multi-baseline data these multiple solutions can be removed. However, the model inversion becomes ill-conditioned unless the correct baseline and frequency ratios are employed. In this paper we show how wave propagation and scattering models can be used to help devise robust inversion methods for land surface parameter estimation.